“We’re going to have a squall, Jonathan,” said David. “You must look out sharp to shift the sheet when I tell you, and unstep the mast, if necessary, the very moment I say, mind!”

“Right you are,” answered the other, who had now lost all that nervousness for which David used to chaff him when on board the Sea Rover. “You only give the word, old man, and you’ll find me all there.”

The squall, however, passed away without touching them, having vented its force in some other quarter; but the wind veered round to the eastwards, much to David’s disgust, as he had to let the boat’s head fall off from the course he wished to steer, and, strange to say, the great black cloud they had first seen seemed still to face them and keep right ahead, although their direction had been altered—it looked, really, just as if standing like a sentry to bar their progress.

“I don’t know what it can mean,” said David anxiously. “The wind has shifted, so why can’t it shift too?”

“It doesn’t appear so big as it was,” observed Jonathan. “It is gradually narrowing at the bottom as it spreads out on top. And look, David, the end of it, close to the sea, comes down into a point just like a thread.”

Presently, as the boat ran nearer towards the cloud, which seemed to rest stationary over the water, they could see that the sea was churned up around it in a state of violent commotion, and they could hear a peculiar sucking noise rumbling in the air at the same time.

“I tell you what it is,” said David; “although I’ve never seen one before, it must be a waterspout, and we’ll have to give it a wide berth. Look out, Jonathan, for the sheet; I’m going to put the helm up and bring the boat about on the other tack.”

Almost as soon as the cutter turned off at an angle from the direction of the waterspout, although not absolutely going away from it, as the boys were interested in the sight, David uttered another exclamation.

“Gracious goodness, Jonathan!” he ejaculated. “Look, if there isn’t a whale there! And he is going slap at it, as if he is going to bowl it over.”

It was true enough; but, whether the leviathan of the deep had been caught in the maelstrom of the waterspout, or had gone towards it from choice, they could not tell. There he was, however, at all events, circling round in the eddy of the sea at the foot of the cloud, and sending up columns of spray every now and then with the flukes of his tail, as they came down with a bash on the water, like the sound of a Nasmyth steam-hammer.